1. Field of the Invention
The invention relates to a tie rod adjustment open-end wrench for rotating a tie rod hexagonal portion of a toe adjustment tie rod of a motor vehicle.
2. Description of the Related Art
An open-end wrench capable of automatically performing the toe adjustment of a motor vehicle by rotating tie rod hexagonal portions 12 of toe adjustment tie rods 10 as shown in FIG. 6 so as to extend or contract the tie rods 10 has been developed (see, e.g., Japanese Patent Application Publication No. 2000-289640 (JP-A-2000-289640), and Japanese Patent Application Publication No. 2004-17907 (JP-A-2004-17907)).
However, this tie rod adjustment open-end wrench transmits rotation force to the tie rod hexagonal portion 12 by a contact portion that contacts a surface of a corresponding tie rod hexagonal portion 12, or contacts two contiguous surfaces thereof, and is able to securely rotate the tie rod hexagonal portion 12 if the tie rod hexagonal portion 12 has a diameter that is assumed beforehand. However, since the tie rod hexagonal portions 12 vary in diameter from a vehicle model to another, it is often the case that the tie rod hexagonal portions 12 are gripped insufficiently by the tie rod adjustment open-end wrench, or is gripped with the center of the tie rod hexagonal portion 12 being off the center of rotation. Therefore, it is difficult to securely rotate the tie rod hexagonal portion 12.